IT202100015206A1 - METHOD OF CONTROLLING A ROAD VEHICLE WITH INDEPENDENT ENGINES ACTING ON WHEELS ON THE SAME AXLE AND RELATED ROAD VEHICLE - Google Patents

Description

DESCRIPTION

of the patent for industrial invention entitled:

?METHOD FOR CHECKING A ROAD VEHICLE WITH INDEPENDENT ENGINES ACTING ON WHEELS ON THE SAME AXLE AND RELATED ROAD VEHICLE?

TECHNICAL SECTOR

The present invention ? relating to a method of controlling a road vehicle with independent motors acting on wheels of the same axle and to a related road vehicle.

EARLIER ART

Self-locking differentials are known which are configured to vary the distribution of torque so as to favor the transmission of power towards the wheel which rotates faster. slowly (avoiding stalls or skids due, for example, to lifting a wheel or slipping on a low-friction surface, such as a wet one). These devices generally include a clutch system configured to limit the torque transmitted to the fastest rotating drive wheel. quickly to the advantage of the one that runs pi? slowly.

In recent years, various types of electronically controlled limited-slip differentials have also been developed to increase the stability, safety or performance of the vehicle.

In the patent application WO2004087453A1 ? described a road vehicle equipped with an electronically controlled limited slip differential, whose locking percentage? controlled by a control unit to try to stabilize (or make more stable and therefore safe) the road vehicle.

According to what is described in the patent application WO2004087453A1, while going through a bend, the control unit progressively increases the locking percentage of the self-locking differential (that is, it ?closes? the clutch of the self-locking differential to transfer a greater quantity of driving torque towards the wheel engine that rotates more slowly, i.e. towards the wheel inside the curve) when the accelerator pedal is released to stabilize the road vehicle.

According to what is described in the patent application WO2004087453A1, while cornering, the control unit progressively reduces the locking percentage of the self-locking differential (that is, it ?opens? the clutch of the self-locking differential to transfer a greater quantity of driving torque towards the wheel drive that rotates faster, or towards the external wheel of the curve) in the event of pressure (sunk) of the accelerator pedal to improve both stability? of the road vehicle, both acceleration performance in corners; in particular, the reduction of the locking percentage of the limited slip differential ? proportional to the lateral acceleration of the road vehicle, to the speed? of progress of the road vehicle, to the drive torque delivered by the engine, and/or to the gear engaged in the gearbox.

According to what is described in the patent application WO2004087453A1, during travel at speed? substantially constant of a curve, the control unit estimates the state of adherence of the drive wheels to the road surface, and consequently cancels the locking percentage of the self-locking differential when the state of adherence of the drive wheels to the road surface ? far from the grip limit, progressively increases the locking percentage of the self-locking differential when the state of grip of the drive wheels to the road surface approaches the grip limit and finally reduces the locking percentage of the self-locking differential down to zero value when the state of grip of the drive wheels to the road surface? very close to the adhesion limit.

With the advent of electric cars, the concept of differential? been maintained even in cases where there are pi? engines, for example one for the front axle and one for the rear axle. Furthermore, in some cases, where the driving wheels of the same axle are operated by different actuators, software has been implemented which imitates the behavior of an electronically controlled limited slip differential.

All the examples described above, making use of a physical differential, electronically controlled or simulated by software, determine or define a constraint between the speed difference? angle of the driving wheels belonging to the same axle. In particular, these constraints are the cause of lack of optimization from the point of view of performance (a part of the traction torque is in any case transmitted to the wheel with greater angular speed) or comfort, also avoiding being able to oppose unwanted yaws due to unfavorable ground conditions or generated by the failure of an actuator.

DESCRIPTION OF THE INVENTION

Purpose of the present invention? to provide a control method of a road vehicle with independent motors acting on wheels of the same axle and to a related road vehicle, which control method is free from the drawbacks described above, is easy and cheap to implement, and in particular allows to maximize performance when traveling on a track without making the road vehicle unstable.

According to the present invention a method is provided for controlling a road vehicle with independent motors acting on wheels of the same axle shaft and a related road vehicle, according to what is claimed in the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention will come now described with reference to the attached drawings, which illustrate a non-limiting embodiment thereof, in which:

? figure 1 ? a schematic plan view of a road vehicle provided with two separate and independent engines which are controlled in accordance with the present invention;

? figure 2 ? a schematic view of the road vehicle of figure 1 during a curve, highlighting the trajectory, the speed? advancement and trim angle;

? figure 3 ? a schematic diagram showing the logical structure of a control in accordance with the present invention; And

? figure 4 shows a schematic diagram illustrating the structure of a controller shown in figure 3.

PREFERRED EMBODIMENTS OF THE INVENTION

In figure 1, with the number 1 ? indicates as a whole a road vehicle provided with two front wheels 2 and two rear driving wheels 3 (therefore belonging to the same axle, the rear one) which receive the drive torque from a motor propulsion system 4.

The motor propulsion system 4 comprises at least two electric motors 5, each of which independently drives a respective drive wheel 3. The electric motors 5 are preferably arranged in a rear longitudinal and transversely central position. Each of said electric motors 5 ? mechanically connected (by means of reduction or transmission elements 6) to the respective wheel 3 by means of a respective axle shaft 7, integral with a respective rear driving wheel 3.

In some non-limiting and not illustrated cases, each driving wheel 3 ? independently driven by a respective semi-axle 7. In particular, the control method comprises the step of controlling the torque TL, TR delivered to each respective semi-axle towards the first driving wheel 3 or towards the second driving wheel 3 according to a torque required by the driver and independently of the difference in speed? angular between the first and second wheel 3. Pi? precisely, the torque delivered to the drive shafts 7 pu? be delivered by a single actuator (endothermic or electric) of the propulsion system 4.

Each wheel 2 or 3 ? mechanically connected to a chassis of the road vehicle 1 by means of a suspension 8 (partially shown in figure 1), which ? provided with an electronically controlled shock absorber 9, or rather provided with an electric actuator which allows the damping of the electronically controlled shock absorber 9 to be varied (or increased or decreased). By way of example, the electric actuator of each electronically controlled shock absorber 9 could comprise one or more? solenoid valves which modulate the size of the oil passage holes inside the electronically controlled shock absorber 9, or could it comprise a magneto-rheological fluid which modifies its properties? physics as a function of an applied magnetic field.

The road vehicle 1 includes a unit? 10 for electronic control (?ECU?) which, among other things, regulates the behavior of the road vehicle 1 both on a straight line and when traveling around a curve by intervening, as better described below, on the torque delivered by the electric motors 5 towards the 3-wheel drive and possibly in collaboration with the shock absorbers 9 of the suspensions 8. Physically, the unit? 10 control pu? be composed of a single device or more? devices separated from each other and communicating through the CAN network of the road vehicle 1.

In known vehicles, as mentioned above, ? present or simulated an electronically controlled limited slip differential. In this type of device, when is the locking clutch? completely open (that is, the locking percentage ? equal to zero), the self-locking differential ? completely free and the driving torque is equally distributed between the two driving rear wheels (that is, each driving rear wheel receives 50% of the total driving torque regardless of its rotation speed); otherwise, by closing the locking clutch (or by increasing the locking percentage), the self-locking differential begins to lock and the driving torque towards the rear driving wheel which rotates faster is progressively increased. slowly (ie the slower rotating rear drive wheel receives more drive torque than the faster rotating rear drive wheel). In this type of device, the difference in torque that can be delivered to each driving wheel? function of the speed difference? angle of the drive wheels themselves. Furthermore, the differential tends to re-establish the balance mentioned above in the division of the torque between the two driving wheels, thus preventing the differentiation of the torque between the two driving wheels in the event of equal speed? angle of rotation of the driving wheels themselves.

Otherwise, according to the control method described below, the unit? 10 of control, in particular a CTR controller internal to it, ? configured to control the torque delivered by each electric motor 5 to the respective driving wheel 3 as a function of a torque Cin requested by the driver (for example via an accelerator pedal) and independently of the difference in speed? angular between the 3 drive wheels. In this way, for example on the basis of a modality? of driving selected by the driver to favor the ?performance? or the ?ease? driving?, ? Is it possible to differentiate the torque supplied by the motors 5 towards the wheels 3 regardless of what are the speed conditions? angle of the 3 drive wheels. In particular, thanks to the elimination of the aforementioned constraint between the difference in speed? angle and the difference in torque delivered to the wheels 3, ? It is possible to improve the maintenance of a straight trajectory on a bumpy or uneven road.

According to what is illustrated in figure 2, during the journey of a curve the unit? control 10 determines in a known way the variation ?? of an angle? of attitude of the road vehicle 1 (that is the angle included between the longitudinal x axis of the road vehicle 1 and the direction of the forward speed V of the road vehicle 1 in the center of gravity B). ? important to note that the? angle ? trim? different from the yaw angle (ie the angle included between the longitudinal axis x of the road vehicle 1 and a fixed reference on the ground), since the road vehicle 1 can? assume the same yaw angle in the plane assuming angles ? even very different trim levels and vice versa.

In particular, the unit? 10 control determines the variation ??of the angle ? trim and calculates the torque to be delivered to each driving wheel 3 as a function of the variation ?? of the trim angle.

According to the preferred embodiment illustrated in figures 3 and 4, the unit? 10 of control detects, in particular through one or more? unit? measure inertial (per se? known and therefore not more detailed) the speed? ?? of yaw rate of the road vehicle 1. Preferably, the CTR controller calculates the torque TR, TL delivered by each motor 5 towards the respective driving wheel 3 as a function of the speed? ?? of yaw.

Advantageously but not necessarily, the variation ?? of the corner ? trim? calculated without resorting to a numerical derivative of the angle ? of trim of the vehicle, bens? through a non-linear combination of speeds? ?? of yaw (yaw rate), lateral acceleration (detected or determined by known models of the vehicle 1 road) and speed? Linear vx of vehicle 1.

According to the preferred but non-limiting embodiments of figures 3 and 4, the unit? The control 10 detects by means of known methods (measured with suitable sensors or estimated by modeling the road vehicle 1) the vertical forces Fz acting on the driving wheels 3, in particular the rear ones. In this way, the controller CTR calculates the torque TR, TL delivered by each motor 5 towards the respective driving wheel 3 as a function of the distribution Fz% of the vertical forces between the driving wheels 3 (see, for example, figure 4).

Advantageously but not necessarily, the unit? 10, in particular the CTR controller, limits (by means of a suitable slip control SLC) the delivery of the torque TR, TL from each motor 5 towards the respective driving wheel 3 in the event that a desired delivery (given by the sum of a yawing ?TNL contribution and a counter-yawing ?TLIN contribution as better described below) exceeds a limit determined by the adherence of a respective tire installed on one of the 3-wheel drive wheels. In particular, the said limit ? calculated according to known techniques as a function of the properties? of the tyre, of the speed? Vx longitudinal of the vehicle 1 and of the speeds? angular angles VRR and VRL respectively of the right driving wheel 3 and of the left driving wheel 3 (figure 4). Thereby ? It is possible to maintain the advantages deriving from the presence of a differential (ie to prevent one wheel from turning excessively in the absence of grip) without, however, constraining the torque delivery of the other drive wheel and without necessarily tending to distribute the torque equally.

As previously mentioned, advantageously but not necessarily, the CTR controller processes the torque TR, TL to be delivered to each driving wheel (respectively right and left) by adding together the counter yaw contribution ?TLIN (in particular linear) and a yaw contribution ?TNL (especially non-linear). In particular, the counter-yawing contribution ?TLIN and the yawing contribution ?TNL each indicate a torque difference between the two driving wheels 3 belonging to the same RA (rear) axle. Pi? precisely the contributions ?TLIN counter yaw ?TNL yaw are values in Nm which indicate, of a total FZM torque entering the rear axle, how much difference there is in the delivery of the torque between the right driving wheel 3 and the left driving wheel 3.

Advantageously but not necessarily, the contribution ?TLIN counter yaw ? calculated (by the CTR controller) as a function of the variation ?' of the corner ? of trim of the vehicle 1 road, of the speed? ?? of yaw and speed? Longitudinal Vx of the road vehicle 1 itself.

In particular, the contribution ?TLIN counter yaw ? given by the sum of a RT contribution based on the variation ?' attitude angle and a SL contribution based on the yaw rate ?'. Pi? precisely, the RT contribution provides a counter-yawing contribution to the final control output which opposes the most? sudden trajectory. Typically, such variations are caused by road input noise or by both linear and non-linear transient dynamics. In other words, the RT contribution ? relating to the area of dynamic behavior of the road vehicle 1 relating to rectilinearity? and transient.

Otherwise, the SL contribution based on the yaw rate ?' provides a counter-yaw contribution to the final output useful for modulating the stationary lateral response of the road vehicle 1 with respect to the steering inputs (SW) provided by the driver. Through this type of control, ? therefore it is also possible to modify the steering torque perceived by the driver. In modulating (calibrating) the stationary lateral response of the vehicle, the multiplicative factor of the yaw rate ?' ? speed dependent? longitudinal Vx and ? dependent on the driver's requests via the LUT table (lookup table).

Advantageously but not necessarily, the contribution ?TNL yawing ? calculated (by the CTR controller) as a function of the lateral dynamics VDL of the vehicle (figure 3), in turn a function of the difference TR-TL of torque delivered by each respective motor 5 of the same axle RA, preferably by means of a geometric relation function of track of the said RA axis and radius of the 3 drive wheels.

In particular, preferably, the relationship between TR-TL and MZ ? uniquely determined by the vehicle dynamics equations (i.e. not by the CTR control). In detail, this relationship is expressed in a multiplicative gain given by vehicle track t and wheel radius R, where MZ = 0.5*(TR-TL)/R*t.

In particular, the contribution ?TNL yawing ? given by the product between the FZ% distribution of the vertical forces between the 3 drive wheels and the total incoming FZM torque at the rear axle. In detail, the distribution FZ% of the vertical forces between the 3 drive wheels indicates the percentage of vertical force acting on the right and left 3 drive wheels with respect to the total acting on the rear axle RA. The block % indicated in figure 4 indicates a simple percentage calculation in which the vertical forces of each driving wheel 3 are divided by the total forces FZ acting on the axis RA. Pi? precisely, the couple FZM ? controlled by the driver via a suitable pedal and substantially corresponds to an input torque Ti (figure 3), i.e. the traction or braking torque request supplied on the basis of the condition of at least one pedal (for example accelerator). In this way, while having to respect this request for torque from the driver, the same pu? be divided freely between the 3-wheel drive based on the vehicle conditions, without being subject to the limits due to the difference in speed? between the driving wheels of prior art systems.

In some non-limiting cases, the control unit 10 ? configured to control the torque TR delivered by the respective motor 5 towards the right driving wheel 3 so as to compensate for any failure of the motor 5 acting on the left driving wheel 3 and vice versa.

Advantageously but not necessarily, as an alternative or in addition, the control unit 10 ? configured to monitor one or more? actuators other than the motors 5 (for example the suspensions 8, in particular the shock absorbers 9) and control the torques TR, TL delivered to the right driving wheel 3 and/or the left driving wheel 3 so as to compensate for any failures of one or more actuators so as to maintain the desired trajectory T of the road vehicle 1.

According to a non-limiting embodiment, the unit? the control 10 estimates the trajectory T followed by the road vehicle 1 using the measurements provided in real time by a tri-axial gyroscope and by a satellite positioner; in particular, the trajectory T is determined by integrating the accelerations measured by the tri-axial gyroscope twice over time and the measurements provided by the satellite positioner are used to cyclically cancel the position errors which occur in the integration process. Furthermore, the unit? 10 control estimates the speed? V of progress of the road vehicle 1 in the center of gravity B using the measurements provided in real time by the tri-axial gyroscope; in particular, the speed? V of road vehicle 1 in the center of gravity B is determined by integrating once in time the accelerations measured by the tri-axial gyroscope (verifying that the forward speed V of road vehicle 1 in the center of gravity B is actually tangent to the trajectory T followed by road vehicle 1 otherwise, in the event of a significant deviation, at least one further iteration of the calculation is performed by making corrections to the parameters used).

During the course of a curve, the unit? 10 of control determines in real time (for example as previously described) the variation ?' of the corner ? of effective (real) attitude of the road vehicle 1.

According to a possible (but not binding) embodiment, the unit? The control 10 cyclically (for example with a frequency of at least a few tens of Hz) estimates (in a known way) adhesion of the wheels 2 and 3 to the road surface, determines a radius of curvature of the trajectory T of the road vehicle 1 (that is, it determines a degree of curvature of the trajectory T), and determines a speed? V of progress of the road vehicle 1. As a function of the adhesion of wheels 2 and 3 (therefore of the stability of the road vehicle 1), of the radius of curvature of the trajectory T, and of the speed? V of progress l?unit? 10 control cyclically determines the variation ?? of the trim angle.

The unit 10 control detects or calculates the speed? ?? of variation of the angle ? attitude and varies the torque delivered to the driving wheels 3 by the respective electric motors 5.

In the non-limiting embodiment of figure 3, the unit? 10 processes a model VDL of the lateral dynamics of the road vehicle 1, in particular as a function of the steering input SW supplied by the driver (for example angle and its derivatives over time) and of a yawing moment Mz, which ? directly proportional (by means of a G factor of proportionality) to the difference TR-TL of torque supplied by the electric motors 5. In particular, the G factor of proportionality? takes into account the aforementioned geometric relationship as a function of the rear track and the radius of the 3-drive wheels. For the calculation of the lateral dynamics of the road vehicle 1, a disturbance d relating to the road conditions is also considered, in accordance with known algorithms.

Following the elaboration of the VDL model, the unit? 10 control sends in input to the CTR controller a plurality? of inputs, including:

- The variation ?' of the corner ? attitude, or the derivative of? angle? d?attitude calculated, as previously indicated, from a non-linear combination of lateral acceleration, yaw rate ?' and speed? V (all signals available from known sensors on board the road vehicle 1);

- the yaw rate ?', or the speed? vehicle yaw (available from a known type of inertial platform);

- the vertical forces Fz acting on the 3-drive wheels, in particular on the rear wheels (measured with special sensors or estimated through car modelling).

Furthermore, the input torque Ti is supplied to the CTR controller, ie the request for traction or braking torque supplied on the basis of the condition of at least one pedal (for example accelerator).

The CTR controller supplies the TR, TL torques to be supplied at the output towards the motors 5 of the motorized RA axis (rear), sending to the proportionality G factor? their difference TR-TL.

In the embodiment of Figure 4 ? illustrated in diagram form a preferred, but non-limiting, embodiment of the structure of the CTR controller.

In particular, as previously mentioned, the final output of the control (before checking the slip SLC control) is calculated as a sum of the contributions which manage each area of dynamic behavior of the car (yawing and counter-yawing).

In summary, the total FZM torque required (or Ti), thanks to the control described up to now, is divided between the TR and TL torques directed to the 3-wheel drive without constraints related to the speed difference? angle of the same.

? moreover, a calibration of the CTR controller is foreseen, elaborating the right gains, thresholds, saturation tables, etc. (for example K for ?', or the LUT table for Vx or in slip control SCL), such as to pursue a desired vehicle dynamics which maximizes known performance indicators (lap time on the track) and driving pleasure. This calibration allows, at any time, based on the conditions of the car, to make the contribution ?TNL, ?TLIN plus? important.

The control method described above has several advantages.

In the first place, the advantage over a system with mechanical differential consists in the removal of the constraint between torque and speed? angles of the wheels of the same axis.

Furthermore, the aforementioned method allows you to maintain the capacity? stabilizer of a mechanical limited slip differential, while exploiting the potential? offered by freedom to freely deliver different torques between the driving wheels even in conditions in which they have the same speed? angular (this does not happen with known systems).

In addition, the control described above makes it possible to easily maintain a straight trajectory even on a bumpy or inclined road, as well as how to manage, for example according to the position of a manettino or the requests of the driver, the yawing and counter-yawing contributions in order to, for example, favor the first in case the objective is the performance, and the second in case l? the goal is the driveability? vehicle simplified.

Furthermore, the control method described above ? particularly safe, as it allows to oppose an unwanted yaw by the driver, but caused by possible failures detected on other actuators, intervening quickly and effectively in case of need.

Finally, the control method described above ? simple and cheap to implement in a road vehicle 1 equipped with a motor for each driving wheel, as it does not require the addition of any physical component (on the contrary, it is possible to remove the differentials thus facilitating maintenance and the flexibility of the vehicle 1) and ? completely feasible via software. ? important to note that the control method described above does not commit nor? a high capacity? of calculation, n? a large amount? of memory and therefore its implementation ? possible in a unit? control note without the need? of updates or upgrades.

LIST OF FIGURE REFERENCE NUMBERS

1 road vehicle

2 front wheels

3 rear wheels

4 powertrain system

5 electric motors

6 reducer

7 axle shaft

8 suspension

9 shock absorber

10 units? control

B center of gravity

Controller CTR

d disturbance

FZ vertical forces

FZ% distribution of vertical forces

FZM total incoming torque rear axle G factor of proportionality?

K gain

LUT look up table

MZ yawing moment

RA Rear axle

RT contribution

SL contribution

SLC slip control

SW steering angle

T trajectory

You couple inputs

TL left wheel pair

TR right wheel pair

Vx speed? longitudinal

x longitudinal axis

y lateral axis

? trim angle

?' trim angle variation

?TLIN counter yaw contribution

?TNL yawing contribution

?' yaw rate

Claims (14)

R E V E N D I C A T I O N S 1) Control method of a road vehicle (1) driven by a driver and equipped with at least one first driving wheel (3) and a second driving wheel (3) belonging to the same axle (RA), each driving wheel (3) being independently driven by a respective first and second semi-axle (7); the control method comprises the step of controlling the torque (TL, TR) delivered to each respective semi-axle (7) towards the first driving wheel (3) or towards the second driving wheel (3) according to a torque requested by the driver and independently of the difference in speed? corner between the first and second wheel (3). 2) Method according to claim 1, wherein each driving wheel (3) ? operated independently by a respective first and second electric motor (5); the control method comprises the step of controlling the torque (TL, TR) delivered by each respective motor (5) towards the first driving wheel (3) or towards the second driving wheel (3) according to a torque requested by the driver and independently of the difference in speed? corner between the first and second wheel (3). 3) Method according to claim 2, and comprising the further step of determining the variation (??) of an attitude angle (?) of the road vehicle (1), or the angle (?) included between the axis ( x) longitudinal of the vehicle (1) road and the direction of the speed? (V) of advancement of the road vehicle (1) in the center of gravity (B), in which the torque (TL, TR) delivered by each respective motor (5) towards the first or second driving wheel (3) ? calculated according to the variation (??) of the trim angle (?). 4) Method according to claim 3, wherein the variation (??) of the attitude angle (?) ? calculated without resorting to a numerical derivative of the trim angle of the vehicle (1); in particular, through a non-linear combination of speed? (?') of yaw, lateral acceleration and speed? (Vx) linear of the vehicle (1). 5) Method according to any one of the preceding claims, and comprising the further step of detecting, in particular by means of at least one unit, of inertial measurement, a speed? (?') of yaw of the road vehicle (1), in which the torque (TL, TR) delivered by each respective motor (5) towards the first or second driving wheel (3) ? calculated according to the speed? (?') of yaw. 6) Method according to any one of the preceding claims, and comprising the further step of detecting the vertical forces (FZ) acting on the driving wheels (3), in particular the rear ones, measured with suitable sensors or estimated by modeling the road vehicle (1) ; in which the torque (TL, TR) delivered by each respective motor (5) towards the first or second driving wheel (3) ? calculated as a function of the distribution (FZ%) of the vertical forces between the driving wheels. 7) Method according to any one of the preceding claims, and comprising the further step of limiting the torque delivery (TL, TR) from each respective motor (5) towards the first or second driving wheel (3) in the event that a desired delivery exceeds a limit determined by the grip of a respective tire installed on the first or second driving wheel (3). 8) Method according to any one of the preceding claims, wherein the torque (TL, TR) to be delivered to the first and second driving wheel (3) comprises the sum of a counter yaw contribution (?TLIN) and a contribution (?TNL) yawing. 9) Method according to claim 8, wherein the counter yaw contribution (?TLIN) ? calculated according to the variation (??) of an angle (?) of attitude of the road vehicle (1), of the speed? (?') of yaw and speed? (Vx) longitudinal of the road vehicle (1) itself. 10) Method according to claim 8 or 9, wherein the yawing contribution (?TNL) ? calculated according to the difference (TR-TL) of torque delivered by each respective motor (5) of the same axle (RA); in particular according to a geometric relationship function of track of said axis (RA) and radius of the first and second driving wheel (3). 11) Method according to any one of the preceding claims, wherein the control ? carried out on the first and second wheel (3) of a rear axle (RA) of the road vehicle (1). 12) Method according to any one of the preceding claims, and comprising the further step of controlling the torque (TL, TR) delivered by the first motor (5) towards the first driving wheel (3) so as to compensate for any failure of the second motor (5) acting on the second driving wheel (3) and vice versa. 13) Method according to any one of the preceding claims and comprising the further steps of monitoring one or more? actuators (8, 9) different from the first and second motor (5) and the phase of controlling the torques (TL, TR) delivered towards the first and/or second driving wheel (3) so as to compensate for any failures of the one or more actuators (8, 9) maintaining a desired trajectory (T) of the road vehicle (1). 14) Road vehicle (1) including: - at least one first driving wheel (3) and a second driving wheel (3) belonging to the same axle (RA); - at least a first and a second electric motor (5) configured to respectively and independently drive the first and second driving wheels (3); the vehicle (1) being characterized in that it comprises a unit? (10) configured to control the torque (TL, TR) delivered to the first electric motor (5) and the second electric motor (5) by carrying out the method according to any one of the preceding claims.